Body tissue often requires repair and stabilization following trauma such as a fractured bone, torn ligament or tendon, ripped muscle, or the separation of soft tissue from bone. For example, trauma to the rotator cuff usually results in a portion, if not all, of the ligament being torn away from bone. To repair such an injury, the rotator cuff must be repositioned to its anatomically correct location and secured to the bone.
One method of repairing a damaged rotator cuff is through the use of a bone anchor and a suture. A hole is drilled in the bone near where the rotator cuff will be reattached to the bone. Then, an instrument is used to place a mattress stitch with a suture in the detached portion of the rotator cuff. The suture is slideably positioned through the anchor, and the anchor is placed in the bone hole using an insertion instrument. This instrument includes an anvil and mandrel placed in contact with the anchor so that when the anvil and mandrel are moved in opposite directions relative to each other, the anchor is deformed. The deformation locks the anchor within the bone. Thereafter, the suture is tensioned drawing the rotator cuff toward the anchor. A suture lock is then activated by the insertion instrument to thereby pinch the suture between the anchor and suture lock.
In another example, fractured bones are a common injury seen in trauma centers. Sports activities, vehicle accidents, industrial-type incidents, and slip and fall cases are just a few examples of how bones may become fractured. Surgeons in trauma centers frequently encounter many different types of fractures with a variety of different bones. Each bone and each fracture type may require unique procedures and devices for repairing the bone. Currently, a one-solution-fixes-all device is not available to repair fractured bones. Instead, surgeons may use a combination of bone screws, bone plates, and intramedullary rods.
Bone plates may be positioned internal to the skin, i.e. positioned against the fractured bone, or may be positioned external to the skin with rods connecting the bone and plate. Conventional bone plates are particularly well-suited to promote healing of the fracture by compressing the fracture ends together and drawing the bone into close apposition with other fragments and the bone plate. However, one drawback with plates and screws is that with the dynamic loading placed on the plate, loosening of the screws and loss of stored compression can result.
To reduce the potential of loosening, locking screws and a locking bone plate may be used. U.S. Pat. No. 5,085,660 to Lin discloses a locking plate system. The system has multiple locking pins, each with one end formed as a screw to lock in the pending fixation bones or vertebral tubercles, with another end defining rectangular or similarly shaped locking post having a threaded locking end. Near the locking post end, there is formed a stopping protrusion. A plate defines multiple locking bores disposed at one side to be placed over the locking post end until the plate reaches the stopping protrusion on the locking pin. The plate defines multiple threaded screwing bores near the other side to receive locking pin screw. Multiple locking devices fix the side of the plate having locking bores to the locking post end of its locking pins. Multiple screwing pins each have one end formed as a pin to be used for penetrating the threaded screwing bore to lock into the bone or the vertebral tubercle. Another end which forms a head is for holding against the threaded screwing bore of the plate. Threads are provided near the head for the screwing pins to be screwed within the threaded screwing bore of the plate.
An example of an external bone plate system is disclosed in U.S. Pat. No. 6,171,307 to Orlich. Orlich teaches an apparatus and procedure for the external unilateral fracture fixation, fracture compression or enlargement of osseous tissue with a metal or equivalent material slotted forked stick to hold and position the threaded pins in its length, inserted in the bone with multiple fastening slidable screws and their bolts to attach the pins to the slotted forked stick, a solid slidable cube to hold and position the slotted forked stick, a supporting axial bar, and an axial threaded bar. A preferred embodiment includes at least three slotted forked sticks that hold and fix, with the use of compression screws and their bolts, threaded pins that penetrate the proximal and distal fragments of the bone through both corticals. Another preferred embodiment includes slotted forked sticks that adapt to the threaded pins, introduced in the bone, at any degree of inclination or orientation that these pins might have with respect to the bone.
In addition to internal or external bone plates, surgeons sometimes use intramedullary rods to repair long bone fractures, such as fractures of the femur, radius, ulna, humerus, fibula, and tibia. The rod or nail is inserted into the medullary canal of the bone and affixed therein by screws or bolts. After complete healing of the bone at the fracture site, the rod may be removed through a hole drilled in the end of the bone. One problem associated with the use of today's intramedullary rods is that it is often difficult to treat fractures at the end of the long bone. Fastener members, such as bolts, are positioned through the cortical bone and into threaded openings in the rod. However, the number and positioning of the bolt/screw openings are limited at the tip of the rod because of the decreased surface area of the rod and the reduced strength at the tip of the rod. Therefore, fractured bone sections at the distal end of a femur, for example, may not be properly fastened to the intramedullary rod.
Various inventions have been disclosed to repair tissue and fasten implants to tissue. U.S. Pat. No. 5,120,175 to Arbegast et al. discloses a fastener having an elongated shank formed of a shape memory alloy, a head at the upper end of the shank, and an annular segment at the lower end of said shank having a deformed cross-sectional shape suitable for insertion into an opening extending through adjacent workpieces. The annular segment has a frusto-conical trained shape that is larger than this opening. The annular segment radially flares from the deformed shape to an approximation of the trained shape when heated above a critical transformation temperature, thereby securing the fastener in place with respect to the workpieces. Alternatively, a sleeve made of a different material (e.g. aluminum) extending over a portion or the entire length of the fastener can be added for improved deformational characteristics, by providing the same frusto-conical shape through axial contraction of the shank.
U.S. Pat. No. 5,290,281 to Tschakaloff teaches a surgical system including a thermoplastic, body absorbable, bodily tissue fixation plate having a plurality of formations and a plurality of through-bores arranged in alternating relation along with plate. The body absorbable fasteners are adapted for insertion into the through-bores to secure the plate to underlying bodily tissue. The heating apparatus includes a wand having a heating tip of a configuration adapted to substantially matingly cooperate with the formations to facilitate heating and bending of the plate into conformance with the underlying bodily tissue.
U.S. Pat. No. 5,941,901 to Egan discloses an expandable soft tissue fixation assembly for use in anchoring soft tissue to bone. The assembly includes a tab connected to an anchor, a sleeve adapted to surround the anchor, and a flange adapted to hold a soft tissue segment next to a bone. The sleeve is inserted into a blind hole in a bone, and a section of soft tissue is placed over the hole next to the bone. Energy is applied to the flange while a predetermined axial tension is applied to the tab to compress a flared portion of the anchor against the sleeve. An upper tube portion of the anchor and the flange are bonded together, and the applied axial force on the tab separates it from the anchor, leaving the assembly anchored in the bone and the soft tissue section anchored in place between the flange and the bone.
U.S. Pat. No. 7,018,380 to Cole discloses a femoral intramedullary rod system. The rod system is capable of treating a variety of femoral bone fractures using a uniform intramedullary rod design. The system generally comprises an intramedullary rod defining an opening having an upper surface and a transverse member including a bone engaging portion and a connection portion defining a thru-hole with the nail sized to pass therethrough. A pin is selectively coupled to the transverse member to rigidly assemble the transverse member to the nail when the nail is passed through the thru-hole and the pin is received within the opening. In an alternative design, an epiphyseal stabilizer is joined to the nail by a locking member.
Also, U.S. Pat. No. 6,228,086 to Wahl et al. discloses a modular intramedullary nail. The intramedullary nail apparatus comprises a nail having a proximal portion, a middle portion and a distal portion. The proximal portion has a longitudinal slot adapted to receive at least one fixing element and the distal portion has at least one transverse bore. The proximal portion has a longitudinal axial bore. The apparatus further includes a set of inserts, each of which is adapted to be inserted in the longitudinal bore. Each insert has at least one guiding bore, the orientation and position of which is different for each of the inserts.
Another assembly and method to fasten tissue is disclosed in U.S. Pat. No. 6,056,751 to Fenton et al. Fenton teaches a soft tissue fixation assembly comprising an anchor element which is installed in a bone or other tissue, and a joiner element which mates with the anchor element to define a tissue capture region between them. A section of soft tissue is held within the tissue capture region, and energy is transmitted into the joiner element to cause relative vibratory motion between the respective components and localized melting of the contacting portions of the respective components to establish a welded joint. The soft tissue segment is thus fixed to the bone without sutures or other fasteners.
U.S. Pat. No. 6,080,161 to Eaves, III et al. teaches a fastener for securing an osteosynthesis plate to a plurality of bone segments is provided. The fastener in the form of a fastener blank includes an elongated shank adapted for insertion through an opening in the plate and into a hole formed in the bone. The upper end of the shank forms a head that serves to secure the plate to the bone. The elongated shank is constructed of a material which when heated will deform to form a tight fit within the hole drilled in the bone. The fastener is preferably made of a resorbable material. The invention also provides a method for securing a plate to a bone using the fasteners of the invention. A fastener blank is positioned into the hole so that a portion of the blank extends into the hole provided in the bone and another portion overlies the plate. The blank is heated to raise the temperature of the blank above the transition temperature of the material from which it is made and deform the blank into a tight fit within the hole.
U.S. Pat. No. 6,605,090 to Trieu et al. discloses orthopedic implants and methods of treating bone defects. More specifically, but not exclusively, the present invention is directed to non-metallic implants and to methods for intra-operative assembly and fixation of orthopedic implants to facilitate medical treatment. The non-metallic implant assembly can be secured to underlying tissue by a fastener, such as a bone screw, that is capable of swelling on contact with fluid in the underlying tissue. Alternatively, the non-metallic implant assembly can be assembled intra-operatively using a fastener that is adhesively bonded to a bone plate or the bone plate can be deformed using heat, force or solvents to inhibit withdrawal of the fastener. In preferred embodiments, both the fastener and the bone plate are formed of biodegradable material.
Also, U.S. Patent Publication No. 2004/0030341 to Aeschlimann et al. teaches implants at least partially consist of a material that can be liquefied by means of mechanical energy. Particularly suitable materials of this type are thermoplastics (e.g. resorbable thermoplastics) or thixotropic materials. The implants are brought into contact with the tissue part, are subjected to the action of ultrasonic energy and are simultaneously pressed against the tissue part. The liquefiable material then liquefies and is pressed into openings or surface asperities of the tissue part so that, once solidified, it is positively joined thereto. The implantation involves the use of an implantation device comprising a generator, an oscillating element and a resonator, whereby the generator causes the oscillating element to mechanically oscillate, and the element transmits the oscillations to the resonator. The resonator is used to press the implant against the tissue part whereby causing oscillations to be transmitted to the implant. The implants are, for example, pin-shaped or dowel-shaped and are used in lieu of screws for forming connections with bone tissue, whereby the bone tissue is optionally pre-bored for positioning the implant. By virtue of the fact that it is unnecessary to transmit any torsional forces to the implants, these implants can be provided with a design that is weaker, i.e. slimmer than that of known screws made of the same material, and they can be implanted more quickly.
Existing systems and techniques for repairing tissue, like the ones previously described, can be complex, time consuming, lack the characteristic of being employed with precision, be damaging to tissue, and/or fail to provide a robust fixation of tissue. Therefore, there is a need for an apparatus and method for the fixation of tissue that involves reduced technical ability, fewer medical instruments, less time to complete, greater strength and precision, and preservation of living tissue. There is a need for a system that involves the precise application of energy to thermoplastic material to affix tissue and implants within the body.